In systems for supplying consumers or recipients with fluids, such as liquid fuels for the operation of internal combustion engines, the state of the art (e.g., DE 10 2009 008 676 A1) involves connecting filter devices upstream of the associated feed pumps, in order to withhold pollutants endangering the operational reliability. For supply systems for diesel engines, ordinarily a filter device is connected upstream of a pre-feed pump in the intake line for diesel fuel, which filter device acts as a pre-filter to remove the main pollution load, including water, from the fuel supplied to the tank, before the pre-feed pump continues supplying the fuel via a fine mesh filter to the injection pump, which is part of the injector system, for example in the form of a common rail system. In the operation of these systems the filter element of the filter device, as a pre-filter cleans the brunt of the pollutants, is to be replaced after the appropriate operating time. For these operations taking place with an at least partially emptied filter housing, air is introduced into the system, which air must be removed in order to ensure the delivery operation of the pre-feed pump. To this end, in the state of the art hand pumps are used, with which the air can be extracted and which can be connected in conjunction with associated valve devices from the outside on the relevant filter housing. The maintenance work that must be carried out for a filter element replacement is therefore laborious and time-consuming.